Process for the dyeing of synthetic polyamides



United States Patent C) 3,320,021 PROCESS FOR THE DYEING F SYNTHETIC POLYANIIDES Jacques Guenthard, Binningen, Basel-Land, Switzerland, assignor to Sandoz Ltd., also known as Sandoz A.G., Basel, Switzerland No Drawing. Filed Dec. 1, 1965, Ser. No. 510,939 6 Claims. (Cl. 8-39) The use of wool dyes for dyeing synthetic polyamides is known. Dyes which build up well on wool and give fast wool dyeings are used, because experience has shown that the properties of wool dyes are no better on synthetic polyamides than on wood and that it is not worth while to test dyes for synthetic polyamides which give unsatisfactory dyeings on wool.

It has now been found that the known compounds of the formula give valuable dyeings on fibers and fiber materials of synthetic polyamides, although they do not give serviceable dyeings on wool.

In Formula I, R represents low molecular alkyl or cycloalkyl which may be substituted, X represents hydrogen, halogen, low molecular alkyl or alkoxy which may be substituted, n represents 1 or 2, and at least one of the ortho-positions of the phenyl radical relative to the NH group is unsubstituted.

Examples of hydrophobic synthetic linear polyamide fibers are the condensation products of 1,6-hexamethylenediamine and adipic acid (nylon 66) or sebacic acid (nylon 610), the polymerization products of e-caprolactam (nylon 6), the condensation products of w-aminoundecanoic acid (nylon 11) and the heterogeneous condensation products of l,6-hexamethylenediamine, adipic acid and e-caprolactam.

These materials are generally dyed with so-called acid wool dyes, which are dyes that build up on wool from an acid bath and dye this fiber in shades fast to light and to wet treatments, such as washing and perspiration.

According to the teaching of United States Patents 1,821,043 and 2,051,005, N-substituted 1,4-diaminoauthraquinones, in particular thedyes of Examples 4 and 7, respectively, can be used for dyeing wool, but the dyeing of synthetic polyamides is not referred to in these patents. These dyes give unsatisfactory dyeings on wool, the wet fastness properties in particular being insufiicient.

Practical experience has shown that dyes which give unsatisfactory dyeings on Wool also dye synthetic polyamides unsatisfactorily. It was surprising and could in no way be expected that the dyes of Formula I would give valuable dyeings on synthetic polyamides since they are not good for dyeing wool. The wet fastness properties, for instance, of dyeings on synthetic polyamides are substantially better than those of wool dyeings.

The dyes of Formula I are applied to synthetic polyamides preferably at temperatures above 95 C., for example at 98-100 C., or at temperatures up to about 130 C. with pressure; the dyeing times vary from about 30 to 120 minutes, being on the average one hour. The dye bath is set with acetic, formic or sulfuric acid or ammonium acetate or sulfate, or alternatively with a mixture of sodium acetate and an acid, such as sulfuric and acetic acid,

3,320,021 Patented May 16, 1967 to obtain the required pH value; it is advisable to dye in a weakly acid medium at pH 4 to 6, or preferably, 4.5 to 5. The levelness of the dyeings can be promoted and/ or the barry appearance of the material covered by using additions of neutral salts, e.g., sodium sulfate, or of anionic, e.g., sodium dinaphthylmethane disulfonate and highly sulfonated castor oil, or nonionic compounds, e.g., alkylpolyglycol ethers, alkylarylpolyglycol ethers, and the reaction products of alkylamides or fatty acid amides and ethylene oxide.

The cyclohexyl radical in the dyes of Formula I may be unsubstituted or it may bear a methyl group in one of the positions ortho, meta or para to the amino group, in which case a mixture of the three isomeric methylcyclohex'yls is suitable.

The radical R may be a low molecular, substituted or unsubstituted, alkyl having for example 1 to 6 carbon atoms, such as methyl, ethyl, propyl, butyl, chloroethyl, cyanoethyl, hydroxyethyl; or a cycloalkyl radical which may be substituted or unsubstituted, such as cyclohexyl or methylcyclohexyl.

The substituent X of the phenyl nucleus may be hydrogen or a halogen atom (chlorine, bromine, fluorine), a low molecular, substituted or unsubstituted, alkyl (methyl, ethyl, isopropyl, chloroethyl, cyanoethyl, hydroxyethyl, benzyl), or a low molecular, substituted or unsubstituted, alkoxy (methoxy, ethoxy, butoxy). When two substituents are present at least one of the positions ortho to the NH group must be unsubstituted, e.g., Z-methyl- 4-methoxy.

These dyestuffs can be produced, for example, by condensing a l-cyclohexylaminoor l-methylcyclohexylamino-4-aminoethraquinone with a bromobenzene of formula Example 1 parts of nylon 66 yarn in hank form are wetted out and entered into a bath consisting of 6000 parts of water, 4 parts of ammonium sulfate and 1 part of the dye of formula 0 NH o-oH;

| SOsH The bath is raised to 100 in 20 minutes and held at this temperature for 30 minutes, after which the evaporated Water is replaced, 1 part of concentrated acetic acid added and dyeing continued for 30 minutes at 100. The yarn is then removed, rinsed Well with water and dried at 100. The resulting dyeing has an attractive turquoise shade and has very good fastness to light, perspiration, Washing at 3 4 60, rubbing and sublimation, and good fastness to washwherein ing at 80". R is a member selected from the group consisting of Equally good results are obtained on yarn of nylon 6 unsubstituted lower alkyl, unsubstituted cycloalkyl, fiber using this dye and dyeing method. methylcycloalkyl and lower alkyl substituted with a The dye used in this example can be produced as folmember selected from the group consisting of a chlolows: rine atom, cyano and hydroxy;

21.3 parts of 1-cyclohexylamino-4-(4'-rnethoxyphenyl' X is a member selected from the group consisting of a amino)-anthraquinone, prepared by condensing l-cyclohydrogen atom, a chlorine atom, a bromine atom, a hexylamino 4 aminoanthraquinone with 1-bromo-4-mefluorine atom, unsubstituted lower alkyl, unsubstithoxybenzene, are dissolved at 5 to 0 in a mixture 10 tuted lower alkoxy, lower alkyl substituted by amemof 100 parts of 100% sulfuric acid and 20 parts of 25% her selected from the group consisting of a chlorine oleum. The mixture is stirred at 0 until a sample comatom, cyano, 'hydroxy and phenyl, and lower alkoxy pletely dissolves in water, which is the case after about 1 substituted with a member selected from the group hour. It is then run into 400 parts of a mixture of water consisting of a chlorine atom, cyano, hydroxy and and ice, the thereby precipitated dye filtered off with sucphenyl; at least one of the ortho positions of the tion and washed with a little cold water. The filter cake is phenyl radical relative to the NH group being unpasted with water and sufiicient sodium carbonate to insubstituted; and crease the pH value to 7.5. The paste is dried and the n is one of the integers 1 and 2.

dry dye ground to a fine powder.

The following table contains further examples of the application of the invention disclosed herein. These ex- 3. A process according to claim 2, wherein the acid dye is of the formula amples are characterized by the dye base which is convetted by sulfonation into the final dye used, and by the NH shade of the dyeing on nylon 66.

Example Dye Base Shade of Dyeing No. on Nylon 66 H I 2 boyclohexylamino-t-(4methoxy3 Green-blue. O NH- OCHa bromophenyl amino) -anthraquinone. 3 O 3 1-(4methylcyclohexylamina)-4-(4- Do.

met hoxyphenylamino) -authraqui- S 0 3H H0118. 4 1cyglohxylamno-$fltertbutoxy- Turquoise blue.

p eny amino an aquinone. 5 myclohexylaminodkGhethoxw D0 4. A process according to claim 2, wherein the acid pheuylamino)-anthraquiuone. dye 15 Of the formula Having thus disclosed the invention, what I claim is: O 1. In the dyeing of hydrophobic synthetic linear poly- H I amides from -a weakly acid to neutral dyebath with acid dye, the improvement wherein the acid dye is dye of the 40 formula (C 2)n1-H l u F o NHO-tert.C4Hv

5. A process according to claim 2, wherein the acid X dye is of the formula wherein R represents a member selected from the group consisting of substituted and unsubstituted low molecular alkyl and cycloalkyl, X represents a member selected from the group consisting of hydrogen, halogen, substituted and unsub' stituted low molecular alkyl and alkoxy, SOKH n represents one of the integers 1 and 2 and at least one of the ortho positions of the phenyl radical relative to the NH- group is unsubstituted. 2. A process according to claim 1, wherein the acid 6. In the dyeing according to claim 1, the improvement wherein the acid dye is of said formula in which R is a member selected from the group consisting of lower alkyl dye is dye of the formula and lower alkyl substituted with a substituent selected (CHM-PH 5 from the group consisting of chloro, cyano and hydroxy.

0 IH H il References Cited by the Examiner UNITED STATES PATENTS 2,051,005 8/1936 Koeberle 260- X 2,845,443 7/1958 Henderman 8-39 X ll O NH NORMAN o. TORCHIN, Primary Examiner.

S0311 DONALD LEVY, Examiner. 

1. IN THE DYEING OF HYDROPHOBIC SYNTHETIC LINEAR POLYAMIDES FROM A WEAKLY ACID TO NEUTRAL DYEBATH WITH ACID DYE, THE IMPROVEMENT WHEREIN THE ACID DYE IS DYE OF THE FORMULA 